The present invention relates generally to security door locks. More particularly, my invention relates to security locks comprising quick-release latches for emergency egress. The lock preferably employs an audible alarm or other means for signaling an emergency exit or unauthorized opening.
As is well known, incidences of forcible breaking and entering in public and commercial buildings have increased dramatically over the years. Accordingly, the demand for reliable security systems has increased sharply. Public awareness of rising crime rates, increased attention to crime prevention efforts, and insurance considerations give impetus to the development of dependable security systems.
Conventional rim locks are generally unsatisfactory for many applications. They provide only a narrow, usually spring-biased bolt that penetrates a shallow port mounted to the door casing. With minimum force and simple tools, the bolt can be easily pried out of engagement with the catch.
Security "deadbolt" locks, on the other hand, penetrate the door casing and project deeply into a port defined through the door frame. Even with the use of a pry bar, the end of the elongated bolt cannot be easily reached and disengaged from its port. Therefore, the effectiveness of deadbolt locks is acknowledged throughout the industry.
However, the conventional deadbolt lock also has its disadvantages. For example, a deadbolt lock comprises a key access port. A well-equipped intruder may quickly manipulate the key port and gain forcible entry by destroying the locking components in the cylinder. Moreover, the conventional deadbolt lock secures only the unhinged portion of the door. The lock thus does not prevent the would-be intruder from removing the door hinges to gain unauthorized entry.
Paddle arm locks usually found on emergency exits typically comprise a rigid, hollow casing adapted to mount to the interior of the door near the hand grip. A rotatable paddle arm handle mechanically releases an elongated, generally spring-biased latch bolt. These locks commonly comprise some form of built-in alarm system adapted to alert an emergency condition in the building.
However, prior art paddle arm locks known to me do not achieve satisfactory deadbolt action. While they do offer an additional barrier, such locks are also fairly easy to disengage. In addition, the alarm switching system of such locks is easily disabled or inadvertently tripped. Because they are operated infrequently, they become easily jammed or difficult to open.
Hence, it is desired to provide a security locking system that positively locks a door against undesired intrusions and which overcomes the disadvantages associated with typical deadbolt and paddle arm systems.